title: Long-term outcome of the WallFlex partially covered stent for unresectable malignant biliary obstruction: a multicenter single-arm prospective study.
abstract: OBJECTIVE
  Covered metallic stent was developed to prevent tumor ingrowth. However, procedural accidents due to its insertion often occur and migration after long-term insertion causes problems. The WallFlex partially covered stent (WF) with reduced axial force enables stenting along the bile duct. We examined the usefulness of WF placement in an unresectable malignant distal biliary obstruction.
  
  
  METHODS
  We examined procedural accidents, stent obstruction rate, and patency period caused by WF insertion.
  
  
  RESULTS
  Ninety-seven patients were analyzed; procedural accidents caused by WF insertion occurred in 8 patients (7.2%) composed of acute cholecystitis in 3 patients (3.2%), acute pancreatitis in 2 patients (2.1%), acute cholangitis in 1 patient (1%), and other in 1 patient (1%). The stent obstruction rate was 19.6% (19 patients), and obstruction cause includes sludge in 9 patients (9.3%), migration in 4 patients (4.1%), food impaction in 3 patients (3.1%), ingrowth in 1 patient (1%), overgrowth in 0 patients (0%), and unknown in 2 patients (2.1%). The mean stent patency period was 634.918 +/- 66.545 (7-946) days.
  
  
  CONCLUSIONS
  WF has less procedural accidents when inserted into unresectable malignant biliary obstruction patients with reduced migration rate after a long period and low obstruction rate.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sakai
authors.forename: Toshio
authors.initials: T
authors.lastname: Tsuyuguchi
authors.forename: Nobuto
authors.initials: N
authors.lastname: Hirata
authors.forename: Harutoshi
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Kenji
authors.initials: K
authors.lastname: Shimura
authors.forename: So
authors.initials: S
authors.lastname: Nakaji
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Shiratori
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Shin
authors.initials: S
authors.lastname: Tsuchiya
authors.forename: Shigeru
authors.initials: S
authors.lastname: Mikami
authors.forename: Osamu
authors.initials: O
authors.lastname: Yokosuka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000009:adverse effects / Q000295:instrumentation*; D002779:Cholestasis / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy*; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008670:Metals; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications*; D010166:Palliative Care; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D008670:Metals